How Potatoes Went from Mountaintops to the Moon

The process of freeze drying is easily associated with the space age, thanks to its use in making astronaut food, but it’s older than you might think. The first known use of it dates back to the Incas, who were able to naturally freeze dry their food on mountaintops thanks to cold temperatures and thin air. Potatoes were stomped daily to get the moisture out, and sublimation took care of the rest, making for lighter, more lasting food called chuños (which is still made today). This process allowed Incas to store up food for droughts, and Spaniards to try “fresh” potatoes in Europe.

Modern science wasn’t able to artificially reproduce the technique until 1909 when Leon Shackell was the first to freeze dry tissue to preserve it. Even then, it wasn’t until 1933 that freeze-drying was put to practical use by Earl Flosdorf, this time to preserve blood for medical purposes. The process made blood stable and more importantly, usable, without needing refrigeration.

During the second world war, freeze drying caught on as a way to ship blood donations to the British without having it spoil (a major problem at the time). In the meantime, Flosdorf turned his attention to freeze- drying food, developing it into a popular commercial technique. Among other things, this led to the rise of powdered food, starting with freeze-dried coffee.

Though freeze drying isn’t as widely used today, NASA has managed to take the process to greater heights than even the Incas by using the technique for astronaut food. That’s because freeze-drying preserves the structure of food, as well as its vitamins and minerals. It may not be exactly the same as a fresh potato, but as anyone who's sampled astronaut ice cream can attest to, it still tastes pretty good.